Aeroplane propeller



June 2l, 1932. J KRASNODMSKY 1,864,492

AEROPLANE PROP ELLER Filed Jan. l. 1931 Patented June 21, 1932 UNITED STATES PATENT OFFICE JOHN KRASNODMSKY, F MILWAUKEE, WISCONSIN, ASSIGNOR OF PER CENT '10y j ANTON J. KOSS, OF MILWAUKEE, WISCONSIN i i AEBOPLANE PaorELLER This invention relates to improvements in propellers and more particularly to propellers especially adapted for use for the propulsion of aeroplanes, and the like.

One of the objects ofthe present invention is the provision of an improved type of propeller of the multiple blade type wherein the blades are arranged one beneath the other in slightly offset position to increase thel pulling power of the propeller when operating at a high rate of speed.

Another object of the present invention is the provision of a propeller of the multiple blade type, wherein the blades are integrally connected and arranged one beyond the other in slightly offsetrelation, with the blades arranged in sets, and the pitch of each blade of each set corresponding so that the blades will cooperate with each other in the propulsion of the machine, and thus increase the power derived from such a type.

A further object ofthe present invention is the provision of a propeller of the multiple blade type wherein blades are integrally connected one with the other and detachably mounted upon the main hub of the driving shaft, so that any unit of the propeller can be removed or replaced at the will of the operator.

With the above and other objects in view, the invention consists in the novel features of construction, the combination and arrangement of parts hereinafter more fully set forth, pointed out in the claims and shown in the accompanying drawing wherein:

Figure 1 is a front elevation of a propeller constructed in accordance with my invention;

Figure 2 is a sectional view onthe line 2-2 of Figure l; Y

Figure 3 is a detailed section on the line 3-3 of Figure 2; and,

Figure 4 is a perspective view of one unit illust-rating a slightly modified form of the invention.

Referring more particularly to the drawing, it will Vbe noted that a portion of the drive shaft 1 of an aeroplane is illustrated in the drawing as provided with an outer reduced threaded end. Mounted on the drive shaft 1 is the hub 3i of the propeller which isretained in position upon the shaft byineans of aremovable'nut 4. s Y

Y Extending radially from the hub 3 Vand arranged in equal spaced relation are theinf tegrally threaded sleeves 5 having'annular collars 6 at the outer ends thereof and *pro-v vided withannular shoulders 7 adjacent the hub portion. s

As shown inFigures 1 to 3 inclusive, each unit of the propeller includes three blade members comprising the outer blades 8 and thefcentral blade 9.'k It will benoted from the showing in Figure r2,that. the pitch of each blade of this unit is uniform sothat all of the' blades -ofea'ch unit will cooperate. The three blades of each, unit are integrally connected by meansof the transverse webs 10 and the centralblade member .9.is pro-v vided with a threaded stem 11f adapted to 'f5 engage'the threads of the sleeve 5. s

Each one 4ofthe blades 9 is provided with an annularshoulder 12 for engaging each one of the sleeves 5 attheir outer ends.y It willI be notedthatone of thefblades 8`is somewhat 75 longer thanthe other, and the inner endsl of each blade are provided with spaced openings to receive thev ends of the U-bolts`13 and 14. As shown in Figure 2, the U-bolts 13 and 1 t are fitted over the sleeve 5 from opposite directions and the ends of these bolts are passedthrough the spaced apertures in the ends of the two outside blades 8, and the bolts can be arranged along side of one anotherl as the end 'of one blade 8 projects beyondthe end of the other blade 8. Spacing blocks 13y and 14 are positioned between the two outside blades and the sleeve 5 with .the ends of the bolts i123 and 14 passing through suitableiapertures in these blocks; These blocks provide means whereby the two outside blades 8 are maintained 'in equal spaced relation throughtheir lengths with 'the intermediate' blade 9. v f 5 It will be apparent fromthe foregoingthat I have provided a simple and comparatively inexpensive propeller of the multiple blade type which can be quickly attached to a hub on ythe driving axle of an aeroplane and wherein. the several blades of each unit of the propeller cooperate to increase the propulsion of the same.

In Figure 4, I have illustrated a slightly modified form of the invention wherein each unit is provided with a pair of blades, the blade 9 being provided with the threaded stem 1-1v and the blade 8 being provided with spaced apertures 15 whereby the blade 8 can be clamped onto one of the sleeves 5 by means of a U-bolt, or the like. t

In this form of the invention, the blades 8 and 9 are integrally connected by means of the webs 10 and the pitch of both blades is the same so that they will cooperate with one another. Y Y

It will be apparent that each unit of the propeller can be made up of a plurality of blades with each blade cooperating so thatv the unit operates as a Vsingle blade, but the unit is strengthened due to the ynumber of blades used and the integral connection of the blades. Y f

While I have shown and described the pre- 'erred embodiment of my invention, it will be apparent from the foregoing that slight changes may be made in the construction when putting the invention into practice vwithout departing from the spirit of the same or the scope ofthe appended claims.

I claim:

1. A propeller including a hub having radially projecting integrally threaded sleeves, and a plurality of multiple blade units each carrying a threaded stem for detachable engagement with said sleeves,

2. A propeller comprising a hub, a plurality of'individual blade vunits secured to and radiating from said hub, each of said blade units including a plurality of equally distantly spaced blade sections of the same pitch and chord, with one arranged slightly in advance of the other.

. 3, Apropeller comprising a hub having radially projecting integrally threaded sleeves, and a plurality of individualblade units leach including a plurality ofequally distantly spaced blade sections of the same pitch and chord, with one arranged slightly 1n advance of the other, a threaded stem carrled .by one of the blade sections for detachable engagement with a sleeve, a shank eXtension on the other blade sections vdisposed eX- teriorly of and in close proximity to a sleeve, anda U-bolt removably extending through the shank extension and detachably engaging the sleeve. 'Y

In testimony kthat. I claim the foregoing I have hereunto set my hand at Milwaukee, in the county of Milwaukee and State of Wis- JoHN KRAsNonMsKY.

consin, 

